Bug 1691955 - Avoid partial updates to picture cache tiles on Mali-Txxx. r=nical
Bug 1691955 - Avoid partial updates to picture cache tiles on Mali-Txxx. r=nical

Previously we had encountered issues when rendering partial regions of
picture cache tiles on Mali-Gxx devices. These often manifested as
patterns of black squares and rectangles. We worked around this by
ensuring that we always clear and render the entire tile. We have now
had a report of a similar looking problem on a Mali-Txxx devices, so
apply the same workaround there.

Differential Revision: https://phabricator.services.mozilla.com/D105278

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/e653fd72aa0b64b3bdd542d6341e9e6e7a97e10f

servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender